Table 3. Associations between maternal preconception serum ALT concentrations and the risk of MPTB, VPTB, and EPTB among 5,169,812 reproductive-aged women in China from 2013 to 2017.
| ALT level (U/L) | MPTB | VPTB | EPTB | |||||
| No. cases (%) | OR (95% CI) | No. cases (%) | OR (95% CI) | No. cases (%) | OR (95% CI) | |||
| Note: The models were adjusted for maternal age at the last menstrual period, preconception body mass index (BMI), education, nationality, occupation, residence, region, parity, hypertension, hyperglycemia, smoking, drinking, periconception folic acid intake, harmful exposure, history of adverse pregnancy outcomes, and serum hepatitis B surface antigen (HBsAg) status. Abbreviation: MPTB=moderate-to-late preterm birth; VPTB=very preterm birth; EPTB=extremely preterm birth; ALT=alanine aminotransferase; OR=odds ratio; CI=confidence interval. | ||||||||
| Classification Ⅰ | ||||||||
| ≤40 | 268,398 (5.47) | 1.00 (Reference) | 41,378 (0.84) | 1.00 (Reference) | 14,689 (0.30) | 1.00 (Reference) | ||
| >40 | 16,099 (6.08) | 1.10 (1.08, 1.12) | 2,508 (0.95) | 1.11 (1.07, 1.16) | 920 (0.35) | 1.15 (1.08, 1.23) | ||
| Classification Ⅱ | ||||||||
| <20 | 181,402 (5.63) | 1.07 (1.06, 1.08) | 27,504 (0.85) | 1.05 (1.02, 1.07) | 9,497 (0.29) | 0.98 (0.95, 1.01) | ||
| 20–40 | 86,996 (5.17) | 1.00 (Reference) | 13,874 (0.83) | 1.00 (Reference) | 5,192 (0.31) | 1.00 (Reference) | ||
| >40 | 16,099 (6.08) | 1.15 (1.13, 1.17) | 2,508 (0.95) | 1.14 (1.09, 1.19) | 920 (0.35) | 1.14 (1.06, 1.22) | ||